From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from deliverator3.ecc.gatech.edu ([130.207.185.173]:54655 "EHLO deliverator3.ecc.gatech.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752015AbZFHVDY (ORCPT ); Mon, 8 Jun 2009 17:03:24 -0400 Message-ID: <4A2D7C99.3090609@gatech.edu> Date: Mon, 08 Jun 2009 17:03:21 -0400 From: David Ward MIME-Version: 1.0 To: Devin Heitmueller CC: Steven Toth , linux-media@vger.kernel.org Subject: Re: cx18, s5h1409: chronic bit errors, only under Linux References: <4A2CE866.4010602@gatech.edu> <4A2D1CAA.2090500@kernellabs.com> <829197380906080717x37dd1fd8n8f37fb320ab20a37@mail.gmail.com> <4A2D3A40.8090307@gatech.edu> <4A2D3CE2.7090307@kernellabs.com> <4A2D4778.4090505@gatech.edu> <4A2D7277.7080400@kernellabs.com> <829197380906081336n48d6090bmc4f92692a5496cd6@mail.gmail.com> In-Reply-To: <829197380906081336n48d6090bmc4f92692a5496cd6@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: On 06/08/2009 04:36 PM, Devin Heitmueller wrote: > On Mon, Jun 8, 2009 at 4:20 PM, Steven Toth wrote: > >> We're getting into the realm of 'do you need to amplify and/or debug your >> cable network', and out of the realm of driver development. >> Comcast is coming tomorrow to check out the signal quality. They said that they expect to deliver SNR in the range of 33dB - 45dB to the premises. I will let you know how that affects Linux captures. > Steven, > > One thing that is interesting is that he is getting BER/UNC errors > even on ATSC, when he has a 30.2 dB signal. While I agree that the > cable company could be sending a weak signal, 30 dB should be plenty > for ATSC. > > Also, it's possible that the playback application/codec in question > poorly handles recovery from MPEG errors such as discontinuity, which > results in the experience appearing to be worse under Linux. > I am actually comparing the TS files captured under both Linux and Windows side-by-side in the same environment, copying the files to other computers in my home. I can demux the video with Project-X which prints out the errors in the bitstream as it reads them. I can also observe the overall quality by playing it back with VLC, WinDVD, etc. When I use TMPGEnc Authoring Works 4 to read the file, the errors in the bitstream even seem to crash the application -- though obviously TMPGEnc is to blame for that. > I'm going to see if I can find some cycles to do some testing here > with s5h1409/s5h1411 and see if I can reproduce what David is seeing. > > Devin, I would really really appreciate this. I hesitated to e-mail this list for several weeks, because I wanted to investigate thoroughly first and avoid wasting anyone's time as much as possible. I hope you are able to reproduce this. David